1. Field of the Invention
The present invention relates to personal information identification systems and, more specifically, to an identification system which verifies input secret information.
2. Description of the Related Art
In automatic teller machines and the like installed in banking organs, a user is authenticated by his inputting secret data such as a password, whereby use of his account, for instance, by other persons is prohibited. That is, in this type of system, an input password is compared with a preset password and a machine is allowed to start operating when the two passwords coincide with each other. In such a system, a preset password is generally a fixed one. There are known several types of the system including a first type system which allows a user to input passwords a limitless number of times and another type system in which a password input function is locked, i.e., disabled if passwords are input more than a given number of times (refer to Japanese Unexamined Patent Publication No. 62-219048).
The above-described conventional systems have the following disadvantages. In the first type system which allows a user to input passwords a limitless number of times, a password is likely broken by using a computer, for instance. In the other type system in which a password input function is locked to disable subsequent password inputs if passwords are input more than a given number of times, the password input function is locked when wrong passwords are input inadvertently, in which case even the true user is prohibited from using the machine.